text: /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project 2006.
   */
  /* ====================================================================
   * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    licensing@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com). */
  
  #include <openssl/x509.h>
  
  #include <assert.h>
  
  #include <openssl/asn1.h>
  #include <openssl/asn1t.h>
  #include <openssl/bio.h>
  #include <openssl/evp.h>
  #include <openssl/err.h>
  #include <openssl/obj.h>
  
  #include "internal.h"
  
  
  ASN1_SEQUENCE(RSA_PSS_PARAMS) = {
    ASN1_EXP_OPT(RSA_PSS_PARAMS, hashAlgorithm, X509_ALGOR,0),
    ASN1_EXP_OPT(RSA_PSS_PARAMS, maskGenAlgorithm, X509_ALGOR,1),
    ASN1_EXP_OPT(RSA_PSS_PARAMS, saltLength, ASN1_INTEGER,2),
    ASN1_EXP_OPT(RSA_PSS_PARAMS, trailerField, ASN1_INTEGER,3),
  } ASN1_SEQUENCE_END(RSA_PSS_PARAMS)
  
  IMPLEMENT_ASN1_FUNCTIONS(RSA_PSS_PARAMS)
  
  
  /* Given an MGF1 Algorithm ID decode to an Algorithm Identifier */
  static X509_ALGOR *rsa_mgf1_decode(X509_ALGOR *alg) {
    if (alg == NULL || alg->parameter == NULL ||
        OBJ_obj2nid(alg->algorithm) != NID_mgf1 ||
        alg->parameter->type != V_ASN1_SEQUENCE) {
      return NULL;
    }
  
    const uint8_t *p = alg->parameter->value.sequence->data;
    int plen = alg->parameter->value.sequence->length;
    return d2i_X509_ALGOR(NULL, &p, plen);
  }
  
  static RSA_PSS_PARAMS *rsa_pss_decode(const X509_ALGOR *alg,
                                        X509_ALGOR **pmaskHash) {
    *pmaskHash = NULL;
  
    if (alg->parameter == NULL || alg->parameter->type != V_ASN1_SEQUENCE) {
      return NULL;
    }
  
    const uint8_t *p = alg->parameter->value.sequence->data;
    int plen = alg->parameter->value.sequence->length;
    RSA_PSS_PARAMS *pss = d2i_RSA_PSS_PARAMS(NULL, &p, plen);
    if (pss == NULL) {
      return NULL;
    }
  
    *pmaskHash = rsa_mgf1_decode(pss->maskGenAlgorithm);
    return pss;
  }
  
  /* allocate and set algorithm ID from EVP_MD, default SHA1 */
  static int rsa_md_to_algor(X509_ALGOR **palg, const EVP_MD *md) {
    if (EVP_MD_type(md) == NID_sha1) {
      return 1;
    }
    *palg = X509_ALGOR_new();
    if (*palg == NULL) {
      return 0;
    }
    X509_ALGOR_set_md(*palg, md);
    return 1;
  }
  
  /* Allocate and set MGF1 algorithm ID from EVP_MD */
  static int rsa_md_to_mgf1(X509_ALGOR **palg, const EVP_MD *mgf1md) {
    X509_ALGOR *algtmp = NULL;
    ASN1_STRING *stmp = NULL;
    *palg = NULL;
  
    if (EVP_MD_type(mgf1md) == NID_sha1) {
      return 1;
    }
    /* need to embed algorithm ID inside another */
    if (!rsa_md_to_algor(&algtmp, mgf1md) ||
        !ASN1_item_pack(algtmp, ASN1_ITEM_rptr(X509_ALGOR), &stmp)) {
      goto err;
    }
    *palg = X509_ALGOR_new();
    if (!*palg) {
      goto err;
    }
    X509_ALGOR_set0(*palg, OBJ_nid2obj(NID_mgf1), V_ASN1_SEQUENCE, stmp);
    stmp = NULL;
  
  err:
    ASN1_STRING_free(stmp);
    X509_ALGOR_free(algtmp);
    if (*palg) {
      return 1;
    }
  
    return 0;
  }
  
  /* convert algorithm ID to EVP_MD, default SHA1 */
  static const EVP_MD *rsa_algor_to_md(X509_ALGOR *alg) {
    const EVP_MD *md;
    if (!alg) {
      return EVP_sha1();
    }
    md = EVP_get_digestbyobj(alg->algorithm);
    if (md == NULL) {
      OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
    }
    return md;
  }
  
  /* convert MGF1 algorithm ID to EVP_MD, default SHA1 */
  static const EVP_MD *rsa_mgf1_to_md(X509_ALGOR *alg, X509_ALGOR *maskHash) {
    const EVP_MD *md;
    if (!alg) {
      return EVP_sha1();
    }
    /* Check mask and lookup mask hash algorithm */
    if (OBJ_obj2nid(alg->algorithm) != NID_mgf1 ||
        maskHash == NULL) {
      OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
      return NULL;
    }
    md = EVP_get_digestbyobj(maskHash->algorithm);
    if (md == NULL) {
      OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
      return NULL;
    }
    return md;
  }
  
  int x509_rsa_ctx_to_pss(EVP_MD_CTX *ctx, X509_ALGOR *algor) {
    const EVP_MD *sigmd, *mgf1md;
    int saltlen;
    if (!EVP_PKEY_CTX_get_signature_md(ctx->pctx, &sigmd) ||
        !EVP_PKEY_CTX_get_rsa_mgf1_md(ctx->pctx, &mgf1md) ||
        !EVP_PKEY_CTX_get_rsa_pss_saltlen(ctx->pctx, &saltlen)) {
      return 0;
    }
  
    EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(ctx->pctx);
    if (saltlen == -1) {
      saltlen = EVP_MD_size(sigmd);
    } else if (saltlen == -2) {
      saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
      if (((EVP_PKEY_bits(pk) - 1) & 0x7) == 0) {
        saltlen--;
      }
    } else {
      return 0;
    }
  
    int ret = 0;
    ASN1_STRING *os = NULL;
    RSA_PSS_PARAMS *pss = RSA_PSS_PARAMS_new();
    if (!pss) {
      goto err;
    }
  
    if (saltlen != 20) {
      pss->saltLength = ASN1_INTEGER_new();
      if (!pss->saltLength ||
          !ASN1_INTEGER_set(pss->saltLength, saltlen)) {
        goto err;
      }
    }
  
    if (!rsa_md_to_algor(&pss->hashAlgorithm, sigmd) ||
        !rsa_md_to_mgf1(&pss->maskGenAlgorithm, mgf1md)) {
      goto err;
    }
  
    /* Finally create string with pss parameter encoding. */
    if (!ASN1_item_pack(pss, ASN1_ITEM_rptr(RSA_PSS_PARAMS), &os)) {
      goto err;
    }
  
    X509_ALGOR_set0(algor, OBJ_nid2obj(NID_rsassaPss), V_ASN1_SEQUENCE, os);
    os = NULL;
    ret = 1;
  
  err:
    RSA_PSS_PARAMS_free(pss);
    ASN1_STRING_free(os);
    return ret;
  }
  
  int x509_rsa_pss_to_ctx(EVP_MD_CTX *ctx, X509_ALGOR *sigalg, EVP_PKEY *pkey) {
    assert(OBJ_obj2nid(sigalg->algorithm) == NID_rsassaPss);
  
    /* Decode PSS parameters */
    int ret = 0;
    X509_ALGOR *maskHash;
    RSA_PSS_PARAMS *pss = rsa_pss_decode(sigalg, &maskHash);
    if (pss == NULL) {
      OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
      goto err;
    }
  
    const EVP_MD *mgf1md = rsa_mgf1_to_md(pss->maskGenAlgorithm, maskHash);
    const EVP_MD *md = rsa_algor_to_md(pss->hashAlgorithm);
    if (mgf1md == NULL || md == NULL) {
      goto err;
    }
  
    int saltlen = 20;
    if (pss->saltLength != NULL) {
      saltlen = ASN1_INTEGER_get(pss->saltLength);
  
      /* Could perform more salt length sanity checks but the main
       * RSA routines will trap other invalid values anyway. */
      if (saltlen < 0) {
        OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
        goto err;
      }
    }
  
    /* low-level routines support only trailer field 0xbc (value 1)
     * and PKCS#1 says we should reject any other value anyway. */
    if (pss->trailerField != NULL && ASN1_INTEGER_get(pss->trailerField) != 1) {
      OPENSSL_PUT_ERROR(X509, X509_R_INVALID_PSS_PARAMETERS);
      goto err;
    }
  
    EVP_PKEY_CTX *pctx;
    if (!EVP_DigestVerifyInit(ctx, &pctx, md, NULL, pkey) ||
        !EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
        !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, saltlen) ||
        !EVP_PKEY_CTX_set_rsa_mgf1_md(pctx, mgf1md)) {
      goto err;
    }
  
    ret = 1;
  
  err:
    RSA_PSS_PARAMS_free(pss);
    X509_ALGOR_free(maskHash);
    return ret;
  }
  
  int x509_print_rsa_pss_params(BIO *bp, const X509_ALGOR *sigalg, int indent,
                                ASN1_PCTX *pctx) {
    assert(OBJ_obj2nid(sigalg->algorithm) == NID_rsassaPss);
  
    int rv = 0;
    X509_ALGOR *maskHash;
    RSA_PSS_PARAMS *pss = rsa_pss_decode(sigalg, &maskHash);
    if (!pss) {
      if (BIO_puts(bp, " (INVALID PSS PARAMETERS)\n") <= 0) {
        goto err;
      }
      rv = 1;
      goto err;
    }
  
    if (BIO_puts(bp, "\n") <= 0 ||
        !BIO_indent(bp, indent, 128) ||
        BIO_puts(bp, "Hash Algorithm: ") <= 0) {
      goto err;
    }
  
    if (pss->hashAlgorithm) {
      if (i2a_ASN1_OBJECT(bp, pss->hashAlgorithm->algorithm) <= 0) {
        goto err;
      }
    } else if (BIO_puts(bp, "sha1 (default)") <= 0) {
      goto err;
    }
  
    if (BIO_puts(bp, "\n") <= 0 ||
        !BIO_indent(bp, indent, 128) ||
        BIO_puts(bp, "Mask Algorithm: ") <= 0) {
      goto err;
    }
  
    if (pss->maskGenAlgorithm) {
      if (i2a_ASN1_OBJECT(bp, pss->maskGenAlgorithm->algorithm) <= 0 ||
          BIO_puts(bp, " with ") <= 0) {
        goto err;
      }
  
      if (maskHash) {
        if (i2a_ASN1_OBJECT(bp, maskHash->algorithm) <= 0) {
          goto err;
        }
      } else if (BIO_puts(bp, "INVALID") <= 0) {
        goto err;
      }
    } else if (BIO_puts(bp, "mgf1 with sha1 (default)") <= 0) {
      goto err;
    }
    BIO_puts(bp, "\n");
  
    if (!BIO_indent(bp, indent, 128) ||
        BIO_puts(bp, "Salt Length: 0x") <= 0) {
      goto err;
    }
  
    if (pss->saltLength) {
      if (i2a_ASN1_INTEGER(bp, pss->saltLength) <= 0) {
        goto err;
      }
    } else if (BIO_puts(bp, "14 (default)") <= 0) {
      goto err;
    }
    BIO_puts(bp, "\n");
  
    if (!BIO_indent(bp, indent, 128) ||
        BIO_puts(bp, "Trailer Field: 0x") <= 0) {
      goto err;
    }
  
    if (pss->trailerField) {
      if (i2a_ASN1_INTEGER(bp, pss->trailerField) <= 0) {
        goto err;
      }
    } else if (BIO_puts(bp, "BC (default)") <= 0) {
      goto err;
    }
    BIO_puts(bp, "\n");
  
    rv = 1;
  
  err:
    RSA_PSS_PARAMS_free(pss);
    X509_ALGOR_free(maskHash);
    return rv;
  }
  